A number of bloggers uploaded footage of bison running away from the park and voiced concerns of an imminent eruption.

Blogger Jay Lee wrote in a post on his site tatoott1009.com: "Whether I believe this, or whether I don't believe the story or not, I don't know. I can tell you this story I saw this morning about the buffaloes running the street ... whether or not it's because of any activity in Yellowstone or not, I don't know.

"But I'll tell you this, whatever the case may be, that their running away from Yellowstone is an alert of some sort."